Named for all the connections that form a functioning society, Threads is a harrowing look at what might happen when those ties are rent apart by nuclear war. This British TV movie — released during the Cold War — so violently seized on the nuclear anxieties of the time that its premiere was dubbed “the night the country didn’t sleep.” Depressingly, it hasn’t lost that initial resonance, and so it remains a panic attack-inducing watch.

Threads begins in the kitchen-sink vein of a Ken Loach movie. In the northern industrial town of Sheffield, a young couple from different social classes (Reece Dinsdale and Karen Meagher) discover they’re about to be parents — but looming above their small-scale drama are the clouds of war, as televisions and radios blare out the details of escalating tensions between the US and the USSR. And then, it happens: the town is strategically bombed, and Threads unfurls into an unrelenting nightmare. In the documentary-like approach that follows, it spares no graphic or emotional detail, charting both the personal devastation caused by the bomb and the annihilating impact of the nuclear holocaust on all the vital infrastructure we take for granted. In short, one of the bleakest, most terrifying movies ever made.

Threads’ multigenerational timeline, harrowing visuals, and two-pronged focus — taking in the personal and the social consequences of nuclear war — can leave no viewer undisturbed by the bleak picture it paints. Its unrelenting brutality can’t be shrugged off, especially when you know it was made in consultation with experts on the subject (and, remarkably, on a low budget). For all the dread it unleashes, then, Threads makes for an extremely potent anti-war film.